# Copyright (c) 2015, Frappe Technologies Pvt. Ltd. and Contributors
# MIT License. See license.txt

from __future__ import unicode_literals
import frappe
import frappe.utils
import json, jwt
import base64
from frappe import _
from frappe.utils.password import get_decrypted_password
from six import string_types

class SignupDisabledError(frappe.PermissionError): pass

def get_oauth2_providers():
	out = {}
	providers = frappe.get_all("Social Login Key", fields=["*"])
	for provider in providers:
		authorize_url, access_token_url = provider.authorize_url, provider.access_token_url
		if provider.custom_base_url:
			authorize_url = provider.base_url + provider.authorize_url
			access_token_url = provider.base_url + provider.access_token_url
		out[provider.name] = {
			"flow_params": {
				"name": provider.name,
				"authorize_url": authorize_url,
				"access_token_url": access_token_url,
				"base_url": provider.base_url
			},
			"redirect_uri": provider.redirect_url,
			"api_endpoint": provider.api_endpoint,
		}
		if provider.auth_url_data:
			out[provider.name]["auth_url_data"] = json.loads(provider.auth_url_data)

		if provider.api_endpoint_args:
			out[provider.name]["api_endpoint_args"] = json.loads(provider.api_endpoint_args)

	return out

def get_oauth_keys(provider):
	"""get client_id and client_secret from database or conf"""

	# try conf
	keys = frappe.conf.get("{provider}_login".format(provider=provider))

	if not keys:
		# try database
		client_id, client_secret = frappe.get_value("Social Login Key", provider, ["client_id", "client_secret"])
		client_secret = get_decrypted_password("Social Login Key", provider, "client_secret")
		keys = {
			"client_id": client_id,
			"client_secret": client_secret
		}
		return keys
	else:
		return {
			"client_id": keys["client_id"],
			"client_secret": keys["client_secret"]
		}

def get_oauth2_authorize_url(provider, redirect_to):
	flow = get_oauth2_flow(provider)

	state = { "site": frappe.utils.get_url(), "token": frappe.generate_hash(), "redirect_to": redirect_to 	}

	frappe.cache().set_value("{0}:{1}".format(provider, state["token"]), True, expires_in_sec=120)

	# relative to absolute url
	data = {
		"redirect_uri": get_redirect_uri(provider),
		"state": base64.b64encode(bytes(json.dumps(state).encode("utf-8")))
	}

	oauth2_providers = get_oauth2_providers()

	# additional data if any
	data.update(oauth2_providers[provider].get("auth_url_data", {}))

	return flow.get_authorize_url(**data)

def get_oauth2_flow(provider):
	from rauth import OAuth2Service

	# get client_id and client_secret
	params = get_oauth_keys(provider)

	oauth2_providers = get_oauth2_providers()

	# additional params for getting the flow
	params.update(oauth2_providers[provider]["flow_params"])

	# and we have setup the communication lines
	return OAuth2Service(**params)

def get_redirect_uri(provider):
	keys = frappe.conf.get("{provider}_login".format(provider=provider))

	if keys and keys.get("redirect_uri"):
		# this should be a fully qualified redirect uri
		return keys["redirect_uri"]

	else:
		oauth2_providers = get_oauth2_providers()

		redirect_uri = oauth2_providers[provider]["redirect_uri"]

		# this uses the site's url + the relative redirect uri
		return frappe.utils.get_url(redirect_uri)

def login_via_oauth2(provider, code, state, decoder=None):
	info = get_info_via_oauth(provider, code, decoder)
	login_oauth_user(info, provider=provider, state=state)

def login_via_oauth2_id_token(provider, code, state, decoder=None):
	info = get_info_via_oauth(provider, code, decoder, id_token=True)
	login_oauth_user(info, provider=provider, state=state)

def get_info_via_oauth(provider, code, decoder=None, id_token=False):
	flow = get_oauth2_flow(provider)
	oauth2_providers = get_oauth2_providers()

	args = {
		"data": {
			"code": code,
			"redirect_uri": get_redirect_uri(provider),
			"grant_type": "authorization_code"
		}
	}

	if decoder:
		args["decoder"] = decoder

	session = flow.get_auth_session(**args)

	if id_token:
		parsed_access = json.loads(session.access_token_response.text)

		token = parsed_access['id_token']

		info = jwt.decode(token, flow.client_secret, verify=False)
	else:
		api_endpoint = oauth2_providers[provider].get("api_endpoint")
		api_endpoint_args = oauth2_providers[provider].get("api_endpoint_args")
		info = session.get(api_endpoint, params=api_endpoint_args).json()

	if not (info.get("verified_email") or info.get("verified")):
		frappe.throw(_("Email not verified with {0}").format(provider.title()))

	return info

def login_oauth_user(data=None, provider=None, state=None, email_id=None, key=None, generate_login_token=False):
	# NOTE: This could lead to security issue as the signed in user can type any email address in complete_signup
	# if email_id and key:
	# 	data = json.loads(frappe.db.get_temp(key))
	#	# What if data is missing because of an invalid key
	# 	data["email"] = email_id
	#
	# elif not (data.get("email") and get_first_name(data)) and not frappe.db.exists("User", data.get("email")):
	# 	# ask for user email
	# 	key = frappe.db.set_temp(json.dumps(data))
	# 	frappe.db.commit()
	# 	frappe.local.response["type"] = "redirect"
	# 	frappe.local.response["location"] = "/complete_signup?key=" + key
	# 	return

	# json.loads data and state
	if isinstance(data, string_types):
		data = json.loads(data)

	if isinstance(state, string_types):
		state = base64.b64decode(state)
		state = json.loads(state)

	if not (state and state["token"]):
		frappe.respond_as_web_page(_("Invalid Request"), _("Token is missing"), http_status_code=417)
		return

	token = frappe.cache().get_value("{0}:{1}".format(provider, state["token"]), expires=True)
	if not token:
		frappe.respond_as_web_page(_("Invalid Request"), _("Invalid Token"), http_status_code=417)
		return

	user = get_email(data)

	if not user:
		frappe.respond_as_web_page(_("Invalid Request"), _("Please ensure that your profile has an email address"))
		return

	try:
		if update_oauth_user(user, data, provider) is False:
			return

	except SignupDisabledError:
		return frappe.respond_as_web_page("Signup is Disabled", "Sorry. Signup from Website is disabled.",
			success=False, http_status_code=403)

	frappe.local.login_manager.user = user
	frappe.local.login_manager.post_login()

	# because of a GET request!
	frappe.db.commit()

	if frappe.utils.cint(generate_login_token):
		login_token = frappe.generate_hash(length=32)
		frappe.cache().set_value("login_token:{0}".format(login_token), frappe.local.session.sid, expires_in_sec=120)

		frappe.response["login_token"] = login_token


	else:
		redirect_to = state.get("redirect_to")
		redirect_post_login(
			desk_user=frappe.local.response.get('message') == 'Logged In',
			redirect_to=redirect_to,
		)

def update_oauth_user(user, data, provider):
	if isinstance(data.get("location"), dict):
		data["location"] = data.get("location").get("name")

	save = False

	if not frappe.db.exists("User", user):

		# is signup disabled?
		if frappe.utils.cint(frappe.db.get_single_value("Website Settings", "disable_signup")):
			raise SignupDisabledError

		save = True
		user = frappe.new_doc("User")
		user.update({
			"doctype":"User",
			"first_name": get_first_name(data),
			"last_name": get_last_name(data),
			"email": get_email(data),
			"gender": (data.get("gender") or "").title(),
			"enabled": 1,
			"new_password": frappe.generate_hash(get_email(data)),
			"location": data.get("location"),
			"user_type": "Website User",
			"user_image": data.get("picture") or data.get("avatar_url")
		})

	else:
		user = frappe.get_doc("User", user)
		if not user.enabled:
			frappe.respond_as_web_page(_('Not Allowed'), _('User {0} is disabled').format(user.email))
			return False

	if provider=="facebook" and not user.get_social_login_userid(provider):
		save = True
		user.set_social_login_userid(provider, userid=data["id"], username=data.get("username"))
		user.update({
			"user_image": "https://graph.facebook.com/{id}/picture".format(id=data["id"])
		})

	elif provider=="google" and not user.get_social_login_userid(provider):
		save = True
		user.set_social_login_userid(provider, userid=data["id"])

	elif provider=="github" and not user.get_social_login_userid(provider):
		save = True
		user.set_social_login_userid(provider, userid=data["id"], username=data.get("login"))

	elif provider=="frappe" and not user.get_social_login_userid(provider):
		save = True
		user.set_social_login_userid(provider, userid=data["sub"])

	elif provider=="office_365" and not user.get_social_login_userid(provider):
		save = True
		user.set_social_login_userid(provider, userid=data["sub"])

	elif provider=="salesforce" and not user.get_social_login_userid(provider):
		save = True
		user.set_social_login_userid(provider, userid="/".join(data["sub"].split("/")[-2:]))

	elif not user.get_social_login_userid(provider):
		save = True
		user_id_property = frappe.db.get_value("Social Login Key", provider, "user_id_property") or "sub"
		user.set_social_login_userid(provider, userid=data[user_id_property])

	if save:
		user.flags.ignore_permissions = True
		user.flags.no_welcome_mail = True
		user.save()

def get_first_name(data):
	return data.get("first_name") or data.get("given_name") or data.get("name")

def get_last_name(data):
	return data.get("last_name") or data.get("family_name")

def get_email(data):
	return data.get("email") or data.get("upn") or data.get("unique_name")

def redirect_post_login(desk_user, redirect_to=None):
	# redirect!
	frappe.local.response["type"] = "redirect"

	if not redirect_to:
		# the #desktop is added to prevent a facebook redirect bug
		redirect_to = "/desk#desktop" if desk_user else "/"

	frappe.local.response["location"] = redirect_to
